1. Field of the Invention
This invention relates to the preparation of polydiorganosiloxanes having alkoxysilethylene endblocking.
2. Background Information
Weyenberg teaches in U.S. Pat. No. 3,175,993, issued Mar. 30, 1965, polyfunctional siloxanes containing terminal alkoxy groups. A method of preparation is shown which reacts a hydrogen endblocked polydiorganosiloxane with an alkoxy silane having a C=C group in the presence of a platinum catalyst.
Klosowski et al. teach in U.S. Pat. No. 4,772,675, issued Sep. 20, 1988, a method of improving the shelf life of silicone elastomeric sealant. A method of producing an alkoxysilethylene endblocked polymer by reacting a dimethylhydrogensiloxy endblocked polydimethylsiloxane with vinyltrimethoxysilane is shown. A method is shown which reacts a vinyl endblocked polydiorganosiloxane with an endcappiug composition of the formula ##STR1##
Krahnke et al. teach in U.S. Pat. No. 4,847,400, issued Jul. 11, 1989, a method of producing a polyalkoxysilyl terminated polydiorganosiloxane by reaction of a hydroxyl endblocked polydiorganosiloxane in the presence of an acidic catalyst with a polyalkoxysilylalkylenedisilazane or a polyalkoxysilylalkylenesilylamine.